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/* $OpenBSD: pte.h,v 1.21 2015/04/12 18:37:54 mlarkin Exp $ */
/* $NetBSD: pte.h,v 1.11 1998/02/06 21:58:05 thorpej Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* pte.h rewritten by chuck based on the jolitz version, plus random
* info on the pentium and other processors found on the net. the
* goal of this rewrite is to provide enough documentation on the MMU
* hardware that the reader will be able to understand it without having
* to refer to a hardware manual.
*/
#ifndef _MACHINE_PTE_H_
#define _MACHINE_PTE_H_
/*
* now we define various for playing with virtual addresses
*/
#define PDSHIFT 22 /* offset of PD index in VA */
#define NBPD (1 << PDSHIFT) /* # bytes mapped by PD (4MB) */
/*
* here we define the bits of the PDE/PTE, as described above:
*
* XXXCDC: need to rename these (PG_u == ugly).
*/
#define PG_V 0x00000001 /* valid entry */
#define PG_RO 0x00000000 /* read-only page */
#define PG_RW 0x00000002 /* read-write page */
#define PG_u 0x00000004 /* user accessible page */
#define PG_PROT 0x00000806 /* all protection bits */
#define PG_WT 0x00000008 /* write through */
#define PG_N 0x00000010 /* non-cacheable */
#define PG_U 0x00000020 /* has been used */
#define PG_M 0x00000040 /* has been modified */
#define PG_PAT 0x00000080 /* PAT bit. (on pte) */
#define PG_PS 0x00000080 /* 4MB page size (on pde) */
#define PG_G 0x00000100 /* global, don't TLB flush */
#define PG_AVAIL1 0x00000200 /* ignored by hardware */
#define PG_AVAIL2 0x00000400 /* ignored by hardware */
#define PG_AVAIL3 0x00000800 /* ignored by hardware */
#define PG_PATLG 0x00001000 /* PAT on large pages */
/* Cacheability bits when we are using PAT */
#define PG_WB (0) /* The default */
#define PG_WC (PG_WT) /* WT and CD is WC */
#define PG_UCMINUS (PG_N) /* UC but mtrr can override */
#define PG_UC (PG_WT | PG_N) /* hard UC */
/*
* various shorthand protection codes
*/
#define PG_KR 0x00000000 /* kernel read-only */
#define PG_KW 0x00000002 /* kernel read-write */
/*
* page protection exception bits
*/
#define PGEX_P 0x01 /* protection violation (vs. no mapping) */
#define PGEX_W 0x02 /* exception during a write cycle */
#define PGEX_U 0x04 /* exception while in user mode (upl) */
#define PGEX_I 0x10 /* instruction fetch blocked by NX */
#endif /* _MACHINE_PTE_H_ */
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